Sudhir Alladi Venkatesh (born 1966) is an American sociologist and urban ethnographer. He is William B. Ransford Professor of Sociology & African-American Studies at Columbia University, a position he has held continuously since 1999. In his work, Venkatesh has studied gangs and underground economies, public housing, advertising and technology. As of 2018, he is the Director of Signal: The Tech & Society Lab at Columbia University.